Disazo dyestuffs



DISSAZU DYESTUFFS Otto Schmid, Muttenz, and Meinrad Hurbin, Basel, Switzen-land, assignors to J. R. Geigy A.-G., Basel, Switzerland No Drawing. Application March 1, 1956 Serial No. 568,718

Claims priority, application Switzerland March 23, 1955 9 t'llaims. (Cl. 260-478) The invention concerns disazo dyestuffs which are suitable for the dyeing of wool from a neutral to weakly acid bath in shades which are fast to wet and light. It also concerns processes for the production of the new disazo dyestuffs, their use for the fast dyeing of polypeptide material and, as industrial product, the material fast dyed with the aid of these dyestufis.

it has been found that valuable disazo dyestuffs are obtained if a diacyl derivative derived from an oaminobenzene sulphonic acid of an organic diamino compound, of an aromatic dihydroxy compound or of an aminohydroxyaryl compound is tetrazotised and coupled with 2 mols of the same or with 1 mol of each of two different Z-aminonaphthalene suiphonic acids which couple in the l-position. lrcferably the tetrazo components are not sulphonated and the benzene rings of the acyl radicals thereof are not further substituted. The benzene rings may, however, advantageously contain non-ionogenic substituents, for example, halogen, alkyl, alkoxy, phenoxy, acylamino, or alkyl sulphonyl groups.

The tetrazo components can be derived from aliphatic, araliphatic, isocyclic-aromatic, hydrocyclic or heterocyclic diamines. Advantageously the acyl radicals are bound to secondary amino groups. This class of tetrazo components which are usable according to the present invention are produced by reacting o nitrobenzene sulphonic acid halides, advantageously in the presence of strong tertiary nitrogen bases such as triethylamine, with secondary diamines; more advantageously the o-nitrobenzene sulphonyl derivatives of primary diamino compounds are alkylated at the amide nitrogen atom by methods known per se. Alkyl, hydroxy alkyl, cycloalkyl, aryloxyalkyl or aralkyl chlorides or bromides are used as alkylating agents. It is of advantage to introduce lower alkyl groups with 1 to 4 carbon atoms into aromatic diamides and to introduce aralkyl or phenoxyalkyl groups into aliphatic diamides. Finally, the nitro groups in the acyl radicals are reduced to amino groups. Starting materials for the tetrazo components according to the present invention are aliphatic diamines such as ethylene diamine, 1.4-diaminobutane, 1.6-diaminohexane, bisaminoethyl ether, bisaminoethyl sulphide, bisaminoethyl glycol ether, alicyclic diamines such as 4-.4'-diamino-dicyclohexyl methane, araliphatic diamines such as 4-aminobenzylamine, 2- or 4-21minopheuoxyethylamine, N.N-diphenylethylene diamine, aromatic diamines such as 1.3- or 1.4-diaminobenzene, 1.4- or 1.5-diaminonaphthalene, in particular however, the bisaminophenyl compounds having phenyl radicals bound direct or by way of bridging members or, possibly also, heterocyclic diamines such as piperazine. A group of starting materials for the production of tetrazo components usable according to the present invention which is of particular technical interest are the bisaminophenyl compounds such as 4.4'-diaminodiphenyl, 4.4'-diaminodibenzyl, bis-aminophenyl alkanes and cycloalkanes, bis-aminophenylethers, thioethers, sulphoxides, sulphones, ketones, ureas, in particular, benzidine and homologues thereof as well as the bis-aminophenyl alkanes and cyclo- States Patent ice 2 alkanes and homologues thereof substituted in the are technically valuable starting materials.

The tetrazo components can also be derived from aromatic dihydroxy compounds which are esterified by the usual methods with o-nitrobenzene sulphonic acid halides, after which the nitro groups are reduced to amino groups. For example 13- or 1.4-dihydroxybenzene, 1.5-, 2.6- and 2.7-dihydroxynaphthalene can be used as starting materials. Of greater technical interest here are also the bishydroxyphenyl compounds, for example the bis-hydroxyphenyl ethers, thioethers, sulphoxides and sulphones, in particular however, the bis-hydroxyphenyl alkanes and cycloalkanes which can easily be produced from aliphatic and cycloaliphatic carbonyl compounds, in particular the ketones and phenols or cresols.

Finally, the tetrazo components can also be derived from amino-hydroxyaryl compounds, for example from 4-hydroxy-l-aminobenzene, from 4-hydroxy-4'-aminodiphenyl, from 2- or 4-amino-3'- or-4-hydroxydiphenyl ether or from 2- or 4-amino-4-hydroxydiphenyl sulphide. Advantageously the bis-o-nitrobenzene sulphonyl derivatives of these starting materials are alkylated at the amide nitrogen atom and then the nitro groups are reduced to amino groups.

The unsulphonated bis-o-aminobenzene sulphonyl compounds usable according to the present invention are tetrazotised advantageously either in inert organic solution in the presence of mineral acids with sodium nitrite or in concentrated sulphuric acid with nitrosyl sulphuric acid. Lower alcohols or lower fatty acids can be used as inert organic solvents.

The Z-aminonaphthalene sulphonic acids which couple in the 1-position usable as azo components according to the present invention can contain preferably only one, or possibly also two sulphonic acid groups. They can also be still further substituted, for example at the nitrogen atom of the amino group by alkyl and possibly by benzyl or phenyl groups; at the naphthalene ring by halogen or alkoxy groups and, in suitable positions, also by hydroxyl groups. Particularly valuable disazo dyestufis according to the present invention are obtained from primary 2- aminonaphthalene monosulphonic acids, e. g. from 2- aminonaphthalene-5-, -6- or -7-sulphonic acid or from 2-amino-8-hydroxynaphthalene-6-sulphonic acid. Further examples of coupling components are: Z-aminonaphthalone-3.6-disulphonic acid, 2-amino-8-hydroxynaphthalene- 3.6-disulphonic acid, Z-methylaminoor 2-ethylaminonaphthalene-5-, -6- or -7-sulphonic acid, Z-methylaminoor Z-ethylamino-8-hydroxynaphthalene-6-sulphonic acid, Z-agnino-S-methoxyor -5-ethoxynaphthalene-7-sulphonic ac1 The coupling is performed in the usual way in the cold with the acid solutions of the alkali salts of the coupling components in the presence of agents which butler the mineral acid such as sodium acetate or sodium formate.

The new disazo dyestuffs correspond to the general formula:

In this formula: C and C each represent the radical of a Z-aminonaphthalene sulphonic acid coupled in the 1-position, advantageously of a Z-aminonaphthalene monosulphonic acid, B and B each represent a benzene ring containing the azo linkage in the o-position to the sulphonyl group, advantageously two identical and not further substituted or possibly non-ionogenically substituted benzene rings, X and X each represent an oxygen atom or a ring \ group wheicin R represent "a lower alkyl radical, an aralkyl radical, a phenoxyalkyl radical or possibly also a phenyl radical or also hydrogen, and A represents the radical of an aliphatic, araliphatic or aromatic diamine, of a diphenol' 'or f an' amino hydroxy-aryl compound and advantageously a 4.4-diphenyl-, a germinate 4.4'-diphenylalkane or cycloalk'ane radical.

In the form of their alkali salts, e. g. the lithium, sodi- NH-CaHt urn, potassium or ammonium salts, the new disazo dye stuffs are powders which dissolve in water with an orange, red to brown colour. They dye polypeptide fibres and in particular, wool, often even from a neutral or weakly acid bathwhich is completely exhausted, in pure orange, yellow-red, red or blue-red shades. The wool dyeings are generally distinguished by excellent wet fastness prop erties and often also by very good fastness to light.

The following examples describe the production of some disazo dyestuffs according to the present invention as well as their use for the dyeing of wool and the table contains further examples obtainable by similar methods, to which, however, the invention is not limited. Where not otherwise stated, in the examples the parts are given as parts by'weight and the temperatures are in degrees centigrade. The relationship of parts by weight to parts by volume is as that of kilograrnmes to litres.

30.3 parts of bis-(o-aminobenzene sulphonyl)-N.N-dibenzyl1-.6-hexamethylene diamine (M. P. 121) are dissolved in 50'parts of hot glacial acetic acid. First parts of concentrated sulphuric acid are carefully added to the solution at and then, while cooling externally and stirring well, the solution of 6.9 parts of sodium nitrite in 35 parts of concentrated sulphuric acid is added at 0 to 10. The whole is stiired for minutes at 0 to 10 and then the solution is diluted by the gradual additron of ice and finally of ice water until the volume is made up to 500 parts. This yellow solution of the tetrazonium compound is poured at 0-10 into solution of the sodium salt of 24.0 parts of Z-amino-S-hydroxynaphthalene-G-sulphonic acid and 100 parts of sodium acetate in 1000 parts of water whereupon the colour changes to red and the disazo dyestufi formed quickly precipitates as a brown-red powder. The mixture is stirred for another 2 hours at 0-10", warmed to 70 and neutralised by sprinkling in sodium carbonate. The disazo dyestuif is then filtered ofi under suction and dried. It is obtained as a dark brown powder which dissolves in hot water Q 0.. C ar...

4 with a red colour and it dyes wool from a neutral to weakly acid bath in purered shades. The Wool dyeings have good wet and light fastness properties.

A disazo dyestutr which dyes wool blue-red is obtained 5 it in the above example, 26.7 parts of Z-ethylamino-S- hydroxynaphthalene-6-sulphonic acid are used as coupling component.

EXAMPLE 2 SOrH 29 parts of 4.4-bis-(o-aminobenzene sulphonyl-N-ethylamino)-2.2-dimethyldiphenyl (M. P. 168) are dissolved in 50 parts of hot glacial acetic acid. The solution is allowed to cool to 20, and first 5 parts of concentrated sulphuric acid are added while stirring well and with external cooling and then a solution of 6.9 parts of sodium nitrite in parts of sulphuric acid is added at 0-10.

After stirring for one hour, ice is added in portions to the yellow solution and then the volume is brought to 500 parts by dilution with ice water. The yellow solution of the tetrazonium compound is poured at 0 to 5 into a solution of the sodium salt of 26 parts of 2 ethylarninonaphthalene-7-sulphonic acid and 100 parts of crystallised sodium acetate in 1000 parts of water. The disazo dyestuflf formed crystallises out very quickly from the red solution in the form of a red powder. The mixture is then stirred for 2 hours at 1020, then heated to 70, neutralised by sprinkling in sodium carbonate and the dyestufi is drawn ofi under suction and dried. It dissolves in hot water with a yellow-red colour and dyes Wool from a neutral to Weakly acid bath in the presence of ammonium sulphate in very pure, light fast yellowish-red shades.

Dyestufis with similar properties are obtained if in the above example 27.5 parts of 4.4-bis-(o-aminobenzene sulphonyl-N-methylamino)-2.2-dimethyldiphenyl or 27.5 parts of 4.4-bis-(o-aminobenzene sulphonyl-N-ethylamino)-diphenyl are used as tetrazo components and other- Wise the same procedure is followed.

EXAMPLE 3 HQN h -N=N 57.8 parts of l.1-bis-[4'-(2"-aminobenzene sulphonyloxy)-phenyl]-cyclohexane (M. P. 15 3-154") are suspended in 150 parts of glacial acetic acid and completely dissolved by the dropwiseaddition while cooling of 30 parts of sulphuric acid. It is tetrazotised by the slow addition at 5-10 of 13.8 parts of sodium nitrite in 35 parts of water. The tetrazo solution is diluted by the gradual addition of 300 parts of ice and then it is poured at l012 while stirring into the solution of the sodium salt of 47.8 parts of 2-amino-8-hydroxynaphthalene-6-sulphonic acid in 500 parts of Water. The mineral acid reaction of the coupling is buttered until Congo red paper is no longer coloured blue by the dropwise addition of a solution of parts of sodium acetate in 300 parts of water within one hour. The red suspension is stirred for another hour at l0-20, then heated to 60 and neutralised. with sodium carbonate. The sodium salt of the disazo dyestuff which precipitates is then drawn ofi under suction and dried.

It is a blue-red powder which dissolves in hot water with a bluish-red colour and dyes wool from a neutral to weakly acid bath in pure, bluish-red shades. The wool The tetrazo components are obtained by reacting 2 mols of 2-nitrobenzene sulphonic acid chloride with the coudensation products of excess phenol with cyclohexanone, acetophenone or decalone-2 and reduction of the nitro groups to amino groups.

EXAMPLE 4 O-o-om-on: im-om-o-O 33.3 parts of bis-(o-aminobenzene sulphonyl)-N.N'-bisphenoxyethyl-1.6-diaminohexane (M. P. 142) are suspended in 100 parts of glacial acetic acid and dissolved by the dropwise addition while stirring at -15 of 7 parts of concentrated sulphuric acid. The solution of 7 parts of sodium nitrite in parts of water is then added dropwise while externally cooling at 0-l0 and then the solution is slowly diluted with 300 parts of ice water. The yellow solution of the tetrazo compound so obtained is then stirred at 0 to 10 into the solution of the sodium salt of 22.3 parts of Z-aminonaphthalene-S-sulphonic acid and 28 parts of crystallised sodium acetate in 500 parts of water whereupon the colour turns orange and some of the disazo dyestuff formed precipitates. After an hour, the mixture is heated to 70, neutralized with sodium carbonate and the dyestufi is precipitated by the gradual addition of 100 parts of sodium chloride. The dyestuii' in the form of an orange-brown powder is filtered off under suction and dried. It dyes Wool from a dyebath containing ammonium sulphate or acetic acid in pure orange shades. The wool dyeings have very good wet and light fastness properties.

HSOa SOaH 53.8 parts of 2.2-bis-[4'-'(2-aminobenzene sulphonyloxy)-phenyl]-propane (M. P. 158-159) are dissolved in l 150 parts of glacial acetic acid, 30 parts of concentrated sulphuric acid are carefully added while cooling and it is tetrazotised at 5-10 by the dropwise addition of the solution of 13.8 parts of sodium nitrite in parts of water. 300 parts of ice are added in portions to the colourless solution whereupon it is poured slowly into the cold solution of the sodium salt of 44.6 parts of 2- aminonaphthalene-7-sulphonic acid in 450 parts of water. The mineral acid reaction is buffered until Congo red paper is no longer coloured blue by the dropwise addition of parts of sodium acetate in 300 parts of water within one hour. The orange suspension is then stirred for one hour at 10-20", then heated to 60 and neutralised by the addition of sodium carbonate. The precipitated disazo dyestutf is filtered otf under suction and dried.

It is an orange powder which dissolves in hot water with an orange colour and dyes wool from a neutral to weakly acid bath in pure orange shades. The wool dyeings have very good milling, sea water and light fastness properties. a

A similar dyestuif is obtained if in the above example, the 2-aminonaphthalene-7-sulphonic acid is replaced by the same number of parts of 2-aminonaphthalene-6-sulphonic acid.

Dyestuffs with similar properties are obtained if in the above example 55.2 parts of 2.2-bis-[4'-(2"-aminobenzene is sulphonyloxy)-phenyl]-butane or 59.4 parts of 3.3-bis- [4'- 2-aminob enzene sulphonyloxy) -phenyl] -5- methylhexane are used as tetrazo components and otherwise the same procedure is followed. These tetrazo components are obtained by reacting methylethyl ketone or 2-methyl-hexanone-4 with excess phenol and esterifying the methyl alcoholic solution of the alkali salts of the condensation products obtained with 2 mols of 2-nitrobenzene sulphonic acid chloride and reducing the nitro groups to amino groups.

EXAMPLE 6 parts of wool which have been previously well wetted are entered at 50 into a dyebath containing 3000 parts of Water, 2 parts of the disazo dyestuff obtained according to Example 5, 10 parts of Glaubers salt and 4 parts of ammonium sulphate. The bath is brought to the boil within 15 minutes and boiled for 45 minutes. The bath is completely exhausted and a very pure orange wool dyeing is obtained which is distinguished by good wet fastness and very good light fastness properties.

The disazo dyestuffs obtained according to the other examples can be dyed onto wool in a similar manner. Possibly 1 to 2% of acetic acid can be added to the liquor towards the end of the dyeing so that the disazo dyestuffs according to the present invention which draw less SOsH well from a neutral bath can be completely extracted from the bath.

The following table contains further examples of disazo dyestufis according to the present invention which are produced by processes similar to those described in Examples 1 to 5.

Table No. Tetrazo component diacyl derivative of Coupling component Shade on ridgmg mem er d wool l o-aminobenzene- N.N bis phenoxyethyl 2-amino-8 hydroxy-naphthared.

sulphonyl-. ethylene diamine. lene-G-sulphonlc acid. 2 do Bis-N-benzylamino-ethyl do D0.

sulphide. 3 do Bis;h N -benzylarnino-ethyl do Do.

e er. 4 do 4.4 bis ethylamino 3.3 do Do.

i dimethyldiphenyl. 5 do 4.4 bls ethylamlno 2.2 do Do. dimethyldlphenyl. Y 6 do ..do kfii uonaphthalene-fi-sulphonlo orange.

e le C e i d No- Teiirazo component diacyi derivative oi Coupling component Shade on bridging member 'Wool' 7 o-aminobenzene- 4.4 bis ethylamino 2.2 2 ethyiaminonaphthaiene 6 yellow red.

sulphony1-. dimethyldiphenyi. sulphonic acid. 8 ..do 1.1 bis (4 ethylamino 2-aminonaphthalene-5-su1ph0nic orange.

phenyD-cyciohexane. acid. 9 -.d 2.2-bis-(4-n-butyi-amino' d0 D0.

phenyD-propane. 10 d0 4.4 bis ethyiamino di 2-amino-8-hydroxy-naphthered.

phenyl sulphide. lenc-fi-sulphonic acid. 11. .d0 lA-dihyd 'oxybenzene U 2 aminonaphthalene 7 sul orange.

phonic acid. 12- d0 3.12M?-(4-hydroxyphenyl)- -..d0 D0.

ep ane. 13 4-methy1-2-amino- 2.2-bis-(4-hydroxyphenyi)- 2-amino-S-hydroxynaphthalenered.

bgnzenle enlpropane. 6-su1phonic acid. p ony 1-! 4-methoxy-2- do do Do.

aminohenzene sulphonyi-. 15 5-acetamino-2- ,do 2 aminonaphthalene 7 sul orange.

aminohcnzene phonic acid. su1phonyi-. l6 .do 1.1-bis-(4-hydroxyphcnyi)- 2 amino 8 hydroxynaphthe red. cyclohexane. lene-fi-sulphom'c acid. 17 Z-ammobenzene 2.2-bi's-(4'-hydroxyphenyi)- ...do Do.

suiphonyl-. n-bntane. 1 8 .do 4-hydroxy-1-benzyiamino- 2 aminonaphthalene 5 sul orange.

benzene. phonic acid. 19 do d 2 aminonaphthalene 7 sul Do.

phonic acid. 20 do 2.2 dihydroxy 5.5 di do D0.

Inethyldiphcnyl-methane. 21 .do 2.2-bis-(4-hydroxyphcnyi)- 2-amino-S-mcthoxynaphtha1ene- Do.

propane. 7-sulphonic acid. 22 do 4.4'-bis-ethylaminodiphenyl 2-a1nino-5-ethoxynaphtha1ene- D0.

methane. 7-sulphonic acid. 23 do 4.4 dihydroxydiphcnyl 2-a1ninonaphthalene-S-sulphonic Do. sniphone. acid. 24 ...do 2.2-bis (3 -meI:hyi-4 -hy 2 amino 8 hydroxynaphtha red.

droxyphenyD-propane. 1ene-6-su.iphonic acid. 25 ..do 1.1-bis-(4-hydroxypheny1)- do D0.

l-phenylethane. 26 5-chioro2amino- 4.4 bis ethyl-amino di 2 ethyiamino naphthalene 7 Do.

bialnzexie sulphenyl methane. sulphonic acid. p ODY 27 do do 2-amino-B-hydroxynaphthalenebluered.

fi-suiphonic acid. 1 mol 2-aminonaphtha1ene-3.6- 28 2 b b I at h disuiphonic acid.

amino enzene 1.1- is- 4 -hy oxyp enyl 13 34. cyclohexane. orange 1 mol 2-aminonaphthalene-5- sulphonic acid. 1 mol 2-amino-naphthaiene-3.6- j disuiphonic acid. 29 .410 1.6 bis phcnoxy ethyl Do amino-nhexanc.

1 mol 2-amino-naphthaiene-7- suiphonic acid. 30 "do... 2.2bis-(4 -hydroxypheny1) 2-aminonaphthalene-G-sulphonie Do. propane. acid. 31 5-eh1oro-2-amino- 2.2 dihydroxy 5.5 di do Do.

benzene sulmethyi-diphenyl methphonyi-. ane. 3 2. d o... do 2 aminonaphthalene 7 sul Do.

phonic acid. 33 -2-aminobenzene 4.4-bis-ethyiamino-dicycio- 2 aminonaphthalene 5 sul Do.

snlphonyie. hexyl methane. phonic acid. 34 do Z-amino-8-hydr0xynaphthalenered.

fi-sulphonic acid. 35 4-methyi-2-an1ino- 2.2-bis-(4-hydroxypheny1)- 2 aminonaphthalene 5 sul orange.

benzene sulpropane. phonic acid. phonyl-. 36 4-methoxy-2-aminodo 2 aminonaphthalene 7 sul Do.

benzene snlphonic acid. phony1-. 37 o-aminobenzenedo 2 ethylamino naphthalene 7 yellow-red.

su1phony1-. sulphonic acid. 38 ..do 2.2-bis-(4-hydroxyphenyi)- 2-methyiamino-naphthalene-7- Do.

butane. sulphonic acid. 39 do L4-dihydroxybcnzene 2 aminonaphthaiene 5 sul orange.

phonic acid. 49 do-.. 4.4-dihydroxydiphenyi sul- 2 ethylamino naphthalene 7 yellow-red.

phone. suiphcnic acid. 41 4-niethyi 2nmino- 4.4 bis ethyiamino 3.3 2-a1nino-S-hydroxynaphthalenered.

benzene s u ldimethyidiphenyi. fi-sulphonic acid. phony1-. 42 .do do 2 aminonaphthalene 5 sl l orange.

phonic acid. 43 .do do 2 aminonaphthaiene 7 sul Do.

phonic acid. 44 4-methoxy-2-aminodo 2-amino-8-hydroxynaphthaienered.

benzene sul- G-sulphonic acid. phonyi. 45 do do 2 aminonaphthaiene 5 sui orange.

phonic acid. 46 do do 2 aminonaphthalene 7 sul Do.

phonic a 47 5-acetan1ino-2- .do 2 a1nino-8-hydroxynaphthalenered.

aminobenzene fi-sulphonic acid. sulphonyh. 48 io .do 2 aminonaphthalene 7 sul orange.

phonic acid. 49 o aminobenzene 4.4 bis ethylamine di 2- butyiamino-naphthalene- 7- yellow-red.

suiphonyh. phenyi methane. anlphonic acid.

9 What we claim is: =1. A disazo dyestufi of the general formula:

wherein R represents a member selected from the group consisting of H and lower alkyl radicals, X represents a z Z member selected from the group of H and a hydroxy NH NH group, Y represents a disecondary diamine radical bound R to the SO -groups by means of its aminonitrogen atoms, and Z represents a member selected from the group consisting of H, CH OCH Cl and NHCOCH A 4. A disazo dyestutf of the formula:

SOsH $03K wherein R represents a member selected from the group Z 2 consisting of H and lower alkyl radicals, X represents NE NH a member selected from the group consisting of H and 1 a hydroxy group, Y represents a member selected from the group consisting of a diphenol and a disecondary diamine radical bound to the SO -gro ups by means of X the hydroxy oxygen and the aminomtrogen atoms re spectively, and Z represents a member selected from the 803K 808K group consisting of H, CH OCH C1 and NHCOCH 2. A disazo dyestufi of the general formula:

NH-R R-NH r wherein X represents a member selected from the group 20 consisting of H and OH, Y represents a diphenol radical bound to the SO groups by means of its hydroxy oxygen atoms, and Z represents a member selected from the group consisting of H, CH OCH and Cl. SOSH S03]; 5. A disazo dyestufi of the formula: wherein R represents a member selected from the group consisting of H and lower alkyl radicals, X represents a member selected from the group consisting of H and a hydroxy group, Y represents a diphenol radical bound NE, NH; to the SO -groups by means of its hydroxy oxygen atoms, l I I I and Z represents a member selected from the group con- N=N s0flN-(CH2)fl N-'S0l N=N sisting of H, CH 0cm, (:1 and NHCOCH 5 3. A disazo dyestuff of the general formula: OH I H0- Z Z O O 40 $0311 sous: NH-R R-NH X SOz-YSO: X-

S0811 6. A disazo dyestufi of the formula:

NH] NH:

CH3 I N=N so,-o-C -i -oso, N=N

H; HOsS- SOIH 7. A disazo dyestuif of the formula:

NH: NHQ

(3H2 N=N sol-0-O :--0-s0: N=N

CH3 OH HO SOgH EiOaH 8. A disazo dyestuff of the formula:

NH-CzHs 01H: CH1 CsHr-NH I (3 11! N=N SOr-N QN- o, N=-=N 0:]?! BOIH SOIH No references cited. 

1. A DISAZO DYESTUFF OF THE GENERAL FORMULA: 